3D in-situ temperature measurement by FBGs in a PDMS-CNPs porous sponge for solar driven interfacial evaporation

This study introduces a novel method for in-situ temperature measurement within photothermal porous materials for solar-driven interfacial evaporation. By embedding fiber Bragg gratings (FBGs) sensor arrays into the solar receiver constructed via a PDMS-CNPs sponge, 3D temperature distribution within the porous structure was reconstructed. Effects of the input light intensity and different working modes on the dynamic temperature response and the heat transfer characteristics were investigated. The results reveal that a thermal equilibrium could be quickly established within the photothermal porous material, and the heat loss to the bulk fluid could be significantly reduced by heat insulation configurations. The results highlight the effectiveness of the proposed method in in-situ temperature field monitoring for photothermal porous materials, which can be further applied in solar receiver construction and optimization of the solar evaporator for solar-driven interfacial applications.